Lathe for turning billiard-balls



UNITED STATES PATENT OFFICE.,

LUTHER A. JOHNSON,- OF SAN FRANCISCO, CALIFORNIA.

LATHE FOR TURNING BlLLlAPtD-BALLS.

Specification forming part of Letters Patent No. 39,817, dated September3, 1863..

clear, and exact description of the same, reference being had to theaccompanying drawings, making a part of this speciiication, in which-Figure l is a plan or top view of my invention; Fig. 2, a longitudinalvertical section of the sametaken in the line a: x, Fig. 1, Fig. 3, atransversevertical section ot' the same, taken in the line y y, Fig. l.

Similar letters of reference indicate corresponding parts in the severalgures.

This invention consists in the employment or use of an adjustabletool-rest inconnection with a concave chuck and a revolving center, allarranged in such a manner that billiardballs and other sphericalarticles may be turned very expeditiously and in a perfect manner.

To enable those skilled in the art to fully understand and construct myinvention, I will proceed to describe it.

A represents the bed of a lathe,.and B the head which contains therevolving mandrel C, and D the head which contains the sliding arbor E,on which the center is secuied. The bed A and heads B D may beconstructed in any of the usual or known ways. The revolving mandrel Chas a chuck, G, attached to its inner end, said chuck having a concaveface, a, forming a section of a hollowr sphere, as shown clearly in Fig.2, and on the inner end of the arbor E there nis secured a socket, H,within whicha small rod, I, is itted and allowed to turn freely, saidrod having a collar, b, upon it, which bears against the inner sideofthe front part of the socket, and the inner end of the rod I ispointed and is fitted or bears in a recess, c, in the arbor E. The outerpart of the rod I projects through the front end of the socket H and hasa screwthread cut upon it on which a cylindrical socket, d, is screwedto receive a piece of india-rubber, e, or other suitable yieldingsubstance. The rod I is allowed to turn freelyin the socket H and formsa revolving center for the article being turned. (SeemoreparticularlyFig. 2, in which a ball shown in red is adjusted between the chuck G androd I, the indiarubber e bearing against the ball.) By this arrangementthe article to be turned is firmly secured in the lathe and rotatedwithout being disiigured by center-points, as would be the case inordinary lathes. This is an important feature of the invention.

J represents an adjustable tool-rest comprised of the following parts,to wit: A plate,

f, which is tted transversely in the bed A and is secured therein by ascrew, g, and is provided at each end with a pendent lip, h, throughwhich set-screws t' pass and bear against the bed A to admit of theplate f being properly adjusted in position. (See Fig. 3.) On the uppersurface of the plate f there are two dovetail guides, jj, which arefitted between two similar guides, k le, at the under side of a circularplate, l, which has a pendent nut, m, attached to it, through which ascrew, K, passes, said screw being on a rod which passes through thelower part of the head D, and has a hand-wheel, L, on its outer end. Onthe upper surface of the circular plate l there is an annular guide orway, u, which is fitted in an annular groove, o, in the under side of acircular plate, p, and at the center of the upper side' of the plateLthere is a conical projection, q, which is iitted in a correspondingrecess in the under side of plate p at its center. (See Fig. 3.) Theplate p is secured to the plate l by a central screw, r. The plate p isallowed to turn freely on the plate l, and on" the upper surface ofplate p' there are secured two ways or guides, s s, which are fitted,

between guides t t at the under side of a slide, u, which has anupright, c, at one end of it, in which the cutting-tool w is iitted. Theslide u is adjusted by a screw., M, which has its bearing in an uprightledge, w', on an; arm, c', which projects horizontally from the plate p,said screw working in a nut, b', at.

the under side ot' the slide u.

From the above description it will be seen that the plates l p and slideu may, by meansA of the screw K and nut m, be adjusted in a directionlongitudinally with the bed A of the lathe, and that the slide u may, bymeans of the screw M and nut b', be adjusted in a direction transverselywith the bed A, and by adjusting these parts properly the tool w may bemade by turning plate p to describe a semil ing to the size of thearticle to be turned.

After the operation above described, the ball in the lathe is changed inposition so that its axis of rotation will be at right angles to that inwhich it rst operated upon, and the plate p is turned as before, whichcompletes the work, all parts of the surface of the article being actedupon by the tool.

By this invention the article to be turned may be expeditiously centeredin the lathe, the pressure of the bearing e against the article beingsufficient to keep the latter in the chuck G so as to insure rotation.

Having thus described my invention, what I claiin as new, and desire tosecure by Letters Patent, is

l. The rotating center, formed of the rod I, provided with a collar, b,and fitted in a socket, H, on the arbor E, and also provided with asocket or cap, cl, to receive a piece of indiarubber, e, or othersuitable yielding material, in combination with the concave chuck G,attached to the mandrel C, all arranged substantially as and for thepurpose specified.

2. The tool-rest composed of the adjustable plate l, turning-plate p,and slide u, all arranged to operate in connection with the chuck androtary center, for the purpose set forth.

LUTHER A. JOHNSON.

Witnesses:

Tiros. S. J. DOUGLAS, Y GEO. W. REED.

